System for managing operation of an industrial vehicle to carry a fragile load

ABSTRACT

An industrial vehicle carries loads on which indicators have been placed. A method for controlling the industrial vehicle involves electronically reading a given indicator on a load being carried by the industrial vehicle to obtain a load identifier. Then, employing the load identifier to obtain data from a database, wherein that data indicates whether the load being carried requires delicate handling. In response to the data obtained from a database, restricting operation of the industrial vehicle to provide delicate handling of the load. Restricting the operation may include one or more of limiting a travel speed or acceleration of the industrial vehicle to less than a predefined level, and limiting a speed at which the load being carried is raised and lowered to less than a predetermined level.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a division of U.S. patent application Ser. No.12/423,877 filed on Apr. 15 2009, and claims benefit of U.S. provisionalpatent application no. 61/046,247 filed on Apr. 18, 2008.

STATEMENT CONCERNING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to industrial vehicles, such as lifttrucks; and more particularly to a system for sensing performancecharacteristics of an industrial vehicle and using those characteristicsto manage the operation of the vehicle.

2. Description of the Related Art

Industrial vehicles of various types, including material handlingvehicles, are used to move items inside a factory, a warehouse, afreight transfer station, a store, or other type of facility. In orderto effectively and efficiently operate a warehouse, for example, it isimportant to ensure that the equipment and employees are as productiveas possible. Recent studies, in fact, have indicated that 70 percent to80 percent of the cost of owning and operating an industrial vehicle isattributed to labor. For a warehouse to compete on the global level,continually improving operator productivity is vital to reducing costs.To meet these goals, warehouse management systems are frequentlyemployed to control inventory, ensure proper maintenance of equipment,and to monitor operator and equipment efficiency. In these warehousemanagement systems, a centralized computer system monitors inventoryflow, use of the industrial vehicle, vehicle maintenance status, andoperator performance.

To provide these functions, data is gathered from each industrialvehicle. In order to gather the data, wiring harnesses and sensorstypically are added to the industrial vehicle after manufacture, oftenafter delivery to the warehouse. These wiring harnesses connect sensorsand other devices to a dedicated onboard computer, and provide a numberof connection points within the vehicle. Because of the large number ofconnection points, these add-on systems are susceptible to failure. Inaddition, the post-manufacture sensors provide only limited informationand can be inaccurate. Thus a more optimized system for monitoring avehicle's performance and operation is desired.

Safe operation of an industrial vehicle requires, operator training andskill, good lift truck maintenance and a safe workplace withappropriately configured lift trucks. Fragile loads sometimes fall offand are damaged when the operator drives the industrial vehicle too fastfor conditions in the warehouse. Also certain warehouse environments,such as cold storage areas and areas with potentially explosiveatmospheres, require special industrial vehicles that are designed tooperate in such environments. For example, Standard UL 583, promulgatedby the Underwriters Laboratories of Northbrook, Ill., U.S.A., specifies“spark proof” characteristics for a Type EE industrial vehicle for usein areas where flammable materials are stored. A potential hazard existswhen a vehicle that is not Type EE rated is used in such storage areas.

As industrial vehicles have gotten more sophisticated, with computerizedcontrols for example, maintenance practices have had to changeaccordingly. A particular lift truck model may have numerous optionalfeatures that a user may choose to have added during manufacture.Typically a dealer dispatches a service technician to the warehouse orfactory to perform maintenance and repairs on an industrial vehicle. Theservice technician needs to know exactly which application specificoptions and features have been incorporated into the vehicle beingserviced and may need access to any of several service manualsassociated with the particular vehicle model and the installed optionsand features. This means that in order to service a complete productline of industrial vehicles and different models which have beenmanufactured over many years, the service technician has to be able toaccess a sizable library of manuals and supplementary materials when ina warehouse or factory.

SUMMARY OF THE INVENTION

An industrial vehicle has a computerized controller that receives datafrom a plurality of sensors which monitor different operating parametersof the vehicle. The industrial vehicle has components that communicatewirelessly via a bidirectional warehouse communication system with acomputer system at a facility, such as a warehouse or a factory, wherethe vehicle operates. This enables data regarding the operatingparameters to be sent to the computer system and enables the industrialvehicle to receive data and commands from the computer system.Additionally, the warehouse communication system is connectable througha network, such as the Internet, to remote computers, such as at theheadquarters of the company that operates the facility and at themanufacturer of the vehicle.

The controller on the industrial vehicle in communication with othercomputers enables implementation of various functions which controloperation of the vehicle. One function limits vehicle operation toassist in protecting fragile loads from being damaged by a carelessoperator. The control system on the vehicle reads an indicator on a loadbeing transported by the industrial vehicle and determines from thatindicator whether the load requires delicate handling. If that is thecase, operation of the industrial vehicle is limited to provide suchdelicate handling. For example, the speed and/or rate of acceleration ofthe vehicle may be limited to lower than normal levels.

In different embodiments, reading the indicator on a load employs eithera radio frequency identification tag reader, a bar code reader, or adevice that utilizes a communication protocol defined by IEEE standard1902.1 promulgated by The Institute of Electrical and ElectronicsEngineers, Inc., New York, N.Y., U.S.A.

Another function accumulates data regarding operation of the industrialvehicle to transport loads and analyzes that data to evaluate thevehicle performance. Here, a sensor detects when a load is beingtransported, and the controller onboard the industrial vehicle countseach load, thereby compiling load data. Additional types of data, suchas for example, the weight of each load and the time that each load isbeing transported, also may be detected and added to the load data.

The controller responds to a given event by wirelessly transmitting theload data via a communication system to a computer system. For example,the controller may tabulate the load data every hour or every workshift, at the conclusion of which, the load data is transmitted to thecomputer system at the facility in which the vehicle operates.

The computer system transforms the load data into performance datadenoting operational efficiency of the industrial vehicle. For example,the load data from one industrial vehicle is compared to similar datafrom other industrial vehicles at the facility or at a plurality offacilities. Such caparisons provide an efficiency evaluation of theperformance of one vehicle or one operator.

In another case, the location of an industrial vehicle at a facility isdetected, such as by using the global positioning satellite system orsignals from a wireless communication system. At least one restrictedarea is defined at the facility. The location information is employed todetermine when the industrial vehicle is within the restricted area, inwhich event operation of that vehicle is limited. For example, vehicleoperation is disabled upon entering the restricted area.

In another aspect of this method, an alert area also is defined at thefacility, such as in front of an entrance to the restricted area. Whenthe location of the industrial vehicle is determined to be within thealert area, a notification is issued, for example to remind the vehicleoperator of the proper operating guidelines.

Another function involves operating the industrial vehicle to utilizebattery power efficiently. The battery is recharged when necessary byelectricity from a utility company, which charges a first rate forelectricity delivered during a first period of a day and charges ahigher second rate for electricity delivered during a second period ofthe day. Operation of the industrial vehicle during the second period islimited to prolong battery life. For example, the maximum speed oftravel is limited to lesser than normal at that time. Thus when thebattery is required to be recharged, that recharging likely will occurduring the first period of a day when a lower electric rate is ineffect.

Servicing the industrial vehicle is facilitated by a process in whichvehicle repair information is stored in a database implemented by acomputer system. Upon occurrence of an operating problem, the industrialvehicle generates a fault code designating the operating problem. Thefault code is used to access the database and obtain the repairinformation associated with the operating problem.

In one embodiment, the repair information describes a process fordiagnosing the cause of the operating problem and identifying componentswhich require replacement. Thereafter, other repair information isaccessed which describes a process for replacing the component of theindustrial vehicle which caused the operating problem.

These and other aspects of the invention will become apparent from thefollowing description. In the description, reference is made to theaccompanying drawings which form a part hereof, and in which there isshown a preferred embodiment of the invention. Such embodiment does notnecessarily represent the full scope of the invention and reference ismade therefore, to the claims herein for interpreting the scope of theinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an industrial vehicle including a systemthat provides wireless communications between a vehicle controller and awarehouse computer system in accordance with the present invention;

FIG. 2 is a block diagram of a control system of the industrial vehicle;

FIG. 3 is a back view of the industrial vehicle with a housing removedto illustrate connection of wireless communication transceiver to theindustrial vehicle;

FIG. 4 is an enlarged section of FIG. 3, that is indicated by a dashedoval, illustrating connections to a terminal strip for coupling thewireless communication transceiver to a wiring harness in the industrialvehicle;

FIG. 5 is a circuit diagram of the wiring harness;

FIG. 6 depicts an exemplary vehicle fleet management system in whichindustrial vehicles in a warehouse communicate via a network with acentral computer in the warehouse that is linked to a remote database towhich other computers have access;

FIG. 7 is a block diagram of the centralized computer in the warehouse;

FIG. 8 is a flowchart of a software routine that is executed by thecontrol system of the industrial vehicle to manage operation whiletransporting fragile loads;

FIG. 9 is a flowchart of a software routine that enables the industrialvehicle to accumulate data about the loads that are transported;

FIG. 10 is a flowchart of a software routine that is executed by thecontrol system of the industrial vehicle to prevent operation inrestricted areas; and

FIG. 11 is a floor plan of part of the warehouse with an area to whichaccess is restricted to only certain types of industrial vehicles.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention relates to the operation of an industrial vehicle.Although the invention is being described in the context of a stand-upcounterbalanced lift truck used at a warehouse, the inventive conceptsare applicable to other types of industrial vehicles, and specificallymaterial handling vehicles, and their use in a variety of facilities,such as a factories, a warehouses, freight transfer stations, andstores, for example.

With initial reference to FIG. 1, an industrial vehicle 10, specificallya lift truck, includes an operator compartment 11 with an opening 19 forentry and exit by the operator. Associated with the operator compartment11 are a control handle 14, a floor switch 13, and steering wheel 16. Anantenna 75 for wireless communications with an external warehousingsystem is coupled to the industrial vehicle 10 and is, as described morefully below, connected to an internal vehicle controller 12 (FIG. 2) toprovide bidirectional communications with a warehousing system. Althoughthe industrial vehicle 10 which is shown by way of example as astanding, fore-aft stance operator configuration reach truck, it will beapparent to those of skill in the art that the present invention is notlimited to vehicles of this type, and can also be provided in othertypes of industrial vehicle configurations including, withoutlimitation, material handling vehicles, pallet trucks, lift trucks,orderpickers, sideloaders, stacker/retrieval machines, reach trucks,swing reach trucks, tow tractor, counterbalanced fork lift vehicles, andother industrial trucks. Furthermore, even though the present inventiveconcepts are being described in the context of a battery poweredvehicle, they apply equally well to vehicles with internal combustionengines.

Referring now to FIG. 2, a block diagram of a control system 20 for atypical industrial vehicle 10 in which the present invention can beprovided is illustrated. The control system 20 comprises a vehiclecontroller 12 which is a microcomputer based device that includes memory24 and input/output circuits. The input/output circuits receive operatorinput signals from the operator control handle 14, the steering wheel16, a key switch 18, and the floor switch 13; and provide commandsignals to each of a lift motor control 23 and a drive system 25including both a traction motor control 27 and a steer motor control 29.The drive system 25 provides a motive force for driving the industrialvehicle 10 in a selected direction, while the lift motor control 23drives load carrying forks 31 along a mast 33 to raise or lower a load35, as described below. The industrial vehicle 10 and vehicle controller12 are powered by one or more batteries 37 that are electrically coupledto the vehicle controller, drive system 25, steer motor control 29, andlift motor control 23 through a bank of fuses or circuit breakers 39.

As noted above, the operator inputs include a key switch 18, floorswitch 13, steering wheel 16, and an operator control handle 14. The keyswitch 18 is activated to apply power to the vehicle controller 12,thereby enabling the industrial vehicle 10. The floor switch 13 providesa signal to the vehicle controller 12 for operating the brake 22 toimplement a deadman braking function that disables motion of the vehicleunless the floor switch is activated by the operator.

Rotation of the operator control handle 14 in a vertical plane providesa travel request signal to the vehicle controller 12 that indicates atravel direction and speed for the industrial vehicle 10. A four-wayswitch 15 located on the top of the handle 14 provides a tilt up/downfunction when activated in the forward and back directions and a sideshift right and left function when activated to the right and leftdirections. A plurality of control actuators 41 located on the handle 14direct a number of additional functions, and can include, for example, areach pushbutton, a retract pushbutton, and a horn pushbutton as well asa potentiometer providing a lift function. A number of other vehiclefunctions also can be provided depending on the construction andintended use of the industrial vehicle 10.

The traction motor control 27 drives one or more traction motors 43which is connected to a propulsion wheel 45 to provide motive force tothe industrial vehicle. The speed and direction of the traction motor 43and the associated propulsion wheel are designated by the operator viathe operator control handle 14, and are monitored and controlled throughfeedback derived from a rotation sensor 44. The rotation sensor 44 canbe an encoder or motion sensor coupled to the traction motor 43 and thesignal therefrom is used to measure the distance that the vehicletravels. The rotation sensor signal is used to increment a softwareimplemented odometer on the vehicle. The propulsion wheel 45 is alsoconnected to friction brake 22 through the traction motor 43, to provideboth a service and parking brake function for the industrial vehicle 10.The friction brake 22 can be spring-activated so that it defaults to a“brake-on” state, such that the floor switch 13 and associated brake 22therefore provide the deadman braking function. The operator mustprovide a signal indicating that the deadman brake is to be released todrive the industrial vehicle, here provided by the floor switch 13, asdescribed above. The traction motor 43 is typically an electric motor,and the associated friction brakes 22 can be either electricallyoperated or hydraulically operated devices. Although one friction brake22, traction motor 43, and propulsion wheel 45 are shown, the industrialvehicle 10 typically includes a plurality of these elements.

The steer motor control 29 is connected to drive a steer motor 47 andassociated steerable wheel 49 in a direction selected by the operator byrotating the steering wheel 16, described above. The direction ofrotation of the steerable wheel 49 determines the direction that theindustrial vehicle 10 travels.

The lift motor control 23 sends command signals to control a lift motor51 which is connected to a hydraulic circuit 53 that form a liftassembly for raising and lowering the forks 31 along the mast 33,depending on the direction selected at the control handle 14. In someapplications, the mast 33 can be a telescoping mast, in which case thehydraulic circuit also raises and lowers the mast. As shown here, aheight sensor 59 is provided in the mast control system to provide asignal to the vehicle controller 12 indicating the height of the mast33. The height sensor 59 can be, for example, an encoder, a flow sensorin the hydraulic system, a light beam, or other types of sensors.Similarly, a weight sensor 57 is provided on the forks 31. The weightsensor 57 can be, for example, a load cell, strain gauge, light beam orpressure sensor in the lift system and provides a signal to the vehiclecontroller 12 that indicates whether a load is on the forks, and aweight of the load. A load sensor 58 is mounted on the mast to obtain anidentification of the goods being transported. The load sensor 58, maybe, for example, a radio frequency identification (RFID) tag reader, aRubee™ device that complies with IEEE standard 1902.1, a bar codereader, or other device capable of reading corresponding identifiers onthe goods or the pallet that holds the goods

In addition to providing control signals to the drive and lift controlsystems, the vehicle controller 12 furnishes data to a display 55 thatpresents information to the vehicle operator. That information caninclude, for example, a number of pallets moved, a number of palletsmoved during a period of time (e.g. per hour or per work shift), anaverage number of pallets moved by the vehicle per day, the weight ofeach pallet or load, and identification of the goods being transported.In addition, the display indicates vehicle operating parameters, such asfor example, the speed of travel, battery charge level, hours ofoperation, time of day, and maintenance needed to be performed. Althoughnot shown here, temperature sensors can also be included to monitor thetemperature of the motors and other components. As used herein the terms“speed of travel” and “travel speed” refer to the rate at which theindustrial vehicle 10 moves across the floor of the warehouse.Furthermore, the functions stated hereinafter of restricting or limitingthe speed of travel refers to reducing that speed from the level thatotherwise could be attained by the industrial vehicle. In other words,the operator would be able to drive the industrial vehicle at a greaterspeed, if such restricting or limiting did not occur and is notwarranted.

Referring still to FIG. 2, a number of data input and output devices canalso be connected to the vehicle controller 12, including, for example,vehicle sensors 66 for parameters such as temperature and battery chargelevel, a user input device 67, a GPS receiver 68, a communication port69, and a maintenance service port 72. The user input device 67 allowsthe operator, a supervisor, or other personnel to enter data into thevehicle controller 12, and can be implemented as a touch screen indisplay 55, a keyboard, a series of discrete pushbuttons, a mouse,joystick or other input device as will be apparent to those of ordinaryskill in the art.

The communication port 69 is connected to a wireless communicationdevice 71 that has an antenna 75 for exchanging data with acommunication system in the warehouse or factory in which the industrialvehicle 10 operates. The wireless communication device 71 includes atransceiver 73 for transmitting messages to and receiving messages fromthe warehouse communication system. Preferably the transceiver employsradio frequencies, although other optical, ultrasonic and other forms ofwireless communication can be used. Any one of several communicationprotocols such as Wi-Fi can be used to exchange messages and data viathat communication link. Each industrial vehicle 10 has a uniqueidentifier that enables messages to be specifically communicated to thatvehicle. The unique identifier may be the serial number of theindustrial vehicle or a unique address on the warehouse communicationsystem. The unique identifier usually is included in every message sentto and from the industrial vehicle 10, however some messages arebroadcast to all the industrial vehicles in the warehouse by using abroadcast identifier to which all vehicles respond.

Referring now to FIGS. 3-5, the communication port 69 is provided in thewiring harness of the industrial vehicle 10 adjacent a housing for thevehicle controller 12. The wireless communication device 71 includes amating connector that can be connected directly to the communicationport 69. As shown here, additional connections are made to a terminalstrip to provide power connections to the battery 37. However, it willbe apparent that battery power could also be routed directly throughadditional terminals of the communication port 69. This connectionallows the transmission of sensor data, operational state data, andswitch and control state data from the vehicle controller 12 to externalequipment. Additionally, because of the direct connection to the vehiclecontroller 12, the wireless communication device 71 can receive commandsfrom external equipment and to provide those commands to the vehiclecontroller. Such commands may limit the speed or acceleration of thevehicle, provide data on a display, and disable vehicle operation, aswell as control other functions of the vehicle, as described more fullybelow.

Referring again to FIG. 2, the vehicle controller 12 stores dataregarding the operation of the industrial vehicle 10. That data caninclude number of hours in operation, battery state of charge, and faultcodes encountered. The hours of operation is calculated as a function ofthe time that the key switch 18 is closed, that the vehicle controller12 floor switch 13 is depressed, that the lift motor 51 is active, orthat the industrial vehicle 10 is traveling based on feedback fromrotation sensor 44 connected to the traction motor 43. In addition,operation of the lift can be monitored using the time that the liftmotor 51 is active. Various speed parameters such as speed andacceleration of the vehicle and of the mast 33 can also be monitored.The vehicle operational data is collected and stored in a memory orother storage device within the vehicle controller 12.

The vehicle operational data also can include an operator identifier,such as a name or employee number, which is entered through a user inputdevice 67 into to the vehicle controller 12. Additionally, operatorchecklists, including those mandated by the U.S. Occupational Safety andHealth Administration (OSHA), can be presented to the operator via thedisplay 55. Data acquired from these checklists can be associated withthe operator along with data related to that person's drivingparameters. For example, average vehicle acceleration rates and speedsmay be monitored, as well as collision data, number of pallets moved, orother data useful in monitoring operator performance and efficiency. Theoperator employs the user input device 67 to enter responses to thechecklist items.

Referring now to FIG. 6, a warehouse 100, in which one or moreindustrial vehicles 10 operates, includes a communication system 102that links the vehicles to a centralized warehouse computer system 104.The communication system 102 includes a plurality of wireless accesspoints 106 distributed through a warehouse 100, such as in a shippingdock and goods storage areas. The wireless access points 106 arewireless transceivers that are connection via a conventional local areanetwork 105 or a TCP/IP communications link to the centralized warehousecomputer system 104. Alternatively the wireless access points 106 can bewirelessly coupled, such as through a Wi-Fi link, to the warehousecomputer system 104.

With reference to FIG. 7, the warehouse computer system 104 includes aprocessor 80 which executes program instructions stored in a memory 82that forms part of a storage system 83. The processor 80 is acommercially available device designed to operate with a MicrosoftWindows® operating system, for example. It includes internal memory andI/O control to facilitate system integration and integral memorymanagement circuitry for handling all external memory 82. The processor80 also includes a bus driver which provides a direct interface with amulti-bit bus 84.

The bus 84 is an industry standard bus that transfers data between theprocessor 80 and a number of peripheral devices. Those devices include adisc controller 86 which provides a high-speed transfer of data to andfrom a CD ROM drive 88 and a hard disk drive 90. A graphics controller91 couples the bus 84 to a standard monitor 92 through a standard VGAconnection 94, and a keyboard and mouse controller 95 receives data thatis manually input through a keyboard 93 and mouse 97. The bus 84 alsoconnects to a vehicle communication interface 96 that connects to thewireless access points 106, and an internet interface 98 is provided tolink the warehouse computer system 104 to the Internet.

Returning to FIG. 6, the management computer system 114 at theheadquarters of the warehouse company is similar to that described forthe warehouse computer system 104 in so far as the present invention isconcerned, except that it is not connected via the local area network105 to the wireless access points 106. Thus both warehouse computersystem 104 and the warehouse management computer system 114 execute thesame software for storing, analyzing and reporting the operatinginformation for the industrial vehicles.

The connection of the warehouse computer system 104 to the Internet 108,or other external communication network, couples the warehouse computersystem to a database 110 that stores vehicle specific data provided bythe manufacturer from a manufacturer computer 112. Selected data canalso be accessed by, for example, warehouse management personnel orvehicle dealers, who can connect to the database 110 through theInternet 108 by way of an extranet or similar system.

Data stored in the database 110 can be accessed with reference to theserial number of a specific vehicle or a model number and includes, forexample, the following:

-   -   Vehicle documentation and parts & service manuals,    -   Field service bulletins and other information,    -   Options added (vehicle modification history),    -   As built Bill of Materials,    -   As built vehicle performance information,    -   Service and replacement parts history,    -   Operating history (impacts, hour meters, fault codes, age),    -   Use history (hour meters, fault codes, battery state-of-charge),    -   Sale/resale history, and    -   Projected end of service date.        Data in the database 110 can be associated with the serial        number of a specific vehicle. This serial number can be used to        access detailed information about a particular vehicle.        Additionally, based on the serial number, the appropriate        vehicle documentation, parts and service manuals, and field        service bulletins or other information can be accessed.

Referring still to FIG. 6, during typical operation, each industrialvehicle 10 in a warehouse transmits messages containing operational dataand its serial number through antenna 75 and communication system 102 tothe warehouse computer system 104, which stores the information. Thedata can be transmitted continuously while the vehicle is operating, atdefined time periods, or at the end of a shift. Information gatheredfrom each vehicle 10, then is relayed occasionally through the Internet108 to the database 110 and also may be sent to the warehouse managementcomputer system 114 at the headquarters of the warehouse company.

Because of the bidirectional communications between the vehiclecontroller 12 and the warehouse communication system 102, the warehousecomputer system 104 can also control vehicle operational parameters. Inparticular, the system can control the maximum travel speed andacceleration of the industrial vehicle in both the forward and reversetravel directions. Additionally, the mast velocity and acceleration canalso be controlled, in both up and down directions. Other vehiclefunctions, such as the horn, can also be activated by the warehousecomputer system 104, as an alarm when certain operating conditions aredetected.

Thus, for example, the warehouse control system can correlate the workintensity of a vehicle to the level of wear experienced by keycomponents. For example, if a temperature sensor indicates that thecomponent temperatures are rising at a higher than expected rate, butthe overall level of productivity is not excessive, it could beconcluded that an operator is using the industrial vehicle very hard fora period and then sitting idle. To prevent overheating of the vehicle,the warehouse communication system can limit both the acceleration andmaximum speed of the industrial vehicle. The vehicle operationparameters, such as speed and acceleration, can also be limited tocontrol energy consumption of the vehicle, and to promote “green”vehicle usage.

The data accumulated by the vehicle controller 12 and stored within itsmemory 24 can be used for a variety of purposes in controlling theoperation of the industrial vehicle 10. One function is to limit thespeed and acceleration of the vehicle when a fragile load is beingtransported. This is accomplished by detecting the characteristics ofthe load each time that the forks 31 are raised or lowered along themast 33 as depicted in FIG. 2. When the vehicle controller 12 sends amotion command to the lift motor control 23, the controller alsocommences executing a software load control routine 120 represented bythe flowchart in FIG. 8. That routine commences at step 122 where thevehicle controller inspects the signal from the weight sensor 57 on thefork lift system. If that signal indicates that the forks 31 are nottransporting a load, the routine immediately branches to step 132 atwhich normal operation of the vehicle is restored before the routineends. Such restoration of normal operation occurs when a previouslycarried load is removed from the forks and the weight sensor 57indicates no load.

Alternatively, when the weight sensor 57 indicates that the forks arenow carrying a load at step 122, the routine advances to step 124 wherethe vehicle controller 12 reads the signal from the load sensor 58 thatis mounted on the mast 33 or the forks 31 so as to read an indicatorthat is either on the load 35 or the pallet 56 on which the load isheld. As noted previously, the load sensor 58 may be any one of a numberconventionally known devices for obtaining information from an object.Examples of such sensors include a radio frequency identification tagreader, a Rubee™ device that complies with IEEE standard 1902.1, or abarcode reader. These devices read indicator from the load or palletwhich identifies the load being carried. For example, each pallet 56 mayhave a unique identifier thus distinguishing that pallet from the otherpallets in the warehouse. Regardless of whether the indicator is on theload 35 or the pallet 56 the signal from the load sensor 58 is referredto as “the load identifier”.

Then at step 126, the vehicle controller sends an inquiry message viathe communication port 69 and the wireless communication device 71 inFIG. 2 to the warehouse communication system 102 in FIG. 6. That inquirymessage contains the unique identification number assigned to thatindustrial vehicle 10, which is used as the vehicle's address in thewarehouse communication system 102. The inquiry message also containsthe load identifier which has just been read and a notation that themessage is requesting information about that load. The inquiry messageis transmitted from the industrial vehicle 10 to the warehousecommunication system access point 106 which is nearest to the industrialvehicle. Upon receipt, the access point 106 forwards that message viathe local area network 105 to the centralized warehouse computer system104. When forwarding the inquiry message, the particular access point106 includes its local area network address.

The warehouse computer system 104 recognizes that incoming message as aload query from an industrial vehicle and responds by extracting theload identifier from that message. The load identifier is then utilizedto access a database which contains characteristics of the materialsthat are on each pallet within the warehouse 100. Specifically, thatdatabase information is indexed by the load identifier enabling thewarehouse computer system 104 to obtain information about thecharacteristics of a particular load. Among those characteristics is anindication of whether the load is fragile and thus requires delicatehandling. That fragility indication is conveyed by the warehousecomputer system 104 in a reply message that is addressed to theindustrial vehicle 10 that sent the query. In particular, the industrialvehicle identification number that was carried by the inquiry message iscopied into the reply message as the address of the intended vehiclerecipient. The local area network address of the particular access point106 that processed the inquiry message also is included. The formulatedreply message is then transmitted by the warehouse computer system 104via the local area network 105 to the designated access point 106, whichthen transmits the reply message wirelessly to the specified industrialvehicle. Alternatively, the reply message can be sent to all the accesspoints 106, so that the reply is broadcast throughout the entirewarehouse 100 in case the industrial vehicle 10 has moved out of rangeof the original access point 106.

Referring again to FIG. 8 along with FIG. 2, upon receiving the replymessage from the warehouse computer system 104, the load control routine120 executed by the vehicle controller 12 advances to step 128, wherethe message contents are read to determine whether a fragile load isindicated. If so, the program execution advances to step 130 where thevehicle is set to restricted operation to provide delicate handling ofthe load. That type of handling can be indicated by setting a fragilityflag in the memory of 24 of the vehicle controller 12, which is readevery time the operator desires to operate the traction motor 43 or thelift motor 51. A set fragility flag causes the vehicle controller 12 tolimit the commands sent to the traction motor control 27 and the liftmotor control 23. Thus regardless of the desired motion indicated by theoperator's manipulation of the control actuators 41, the vehiclecontroller 12 limits the travel speed and rate of acceleration of thetraction motor 43 and thus those parameters of the industrial vehicle10. The speed at which the load is raised and lowered also is limited byrestricting operation of the lift motor 51. As a consequence, when afragile or delicate load is being carried, the industrial vehicle isoperated in a manner that is less likely to disturb or damage the load.

If, however, the reply message indicates that the load is not fragile,the load control routine 120 branches from step 128 to step 132 at whichthe fragility flag within the vehicle controller memory 24 is reset toenable full, normal vehicle operation. This removes any restrictions onthe speed or acceleration and thus the vehicle can operate at themaximum levels of those parameters.

Although it is generally desirable to assign a unique identifier to eachpallet of materials within the warehouse so that the particular contentsof the load can be identified for other purposes, the indicator on theload 35 or pallet 36 may simply designate whether or not the load isfragile. In other words, the indicator is not unique to a particularload, but one form of the indicator is used on all fragile load andanother form is used on all non-fragile loads. In this case, the vehiclecontroller 12 does not have to interrogate the central warehousecomputer system 104 for the fragility information, but can determineonboard whether the load is fragile and thus operate the traction motoraccordingly. In this latter case, each industrial vehicle is controlledautonomously.

In either situation, when the industrial vehicle 10 deposits the load atthe end of its transportation and the forks 31 are empty, that conditionis detected at step 122 as there being no load on the forks. As notedpreviously in this condition, a branch occurs to step 132 where thevehicle is reset to normal operation until another fragile load isdetected.

Referring to FIGS. 2 and 9, the load weight sensor 57 can also beutilized to implement another function that tracks the performance andefficiency of the industrial vehicle 10. This function is performed by aload performance routine 170 executed by the vehicle controller 12 eachtime that the lift motor 51 is operated at which time the signal fromweight sensor 57 is examined at step 172 to determine whether a new loadhas just been picked up. Alternatively the load sensor 58 may be used todetermine the presence of a load 35 on the forks 31, however, unless aweight sensor 57 also is included on the vehicle, this technique doesnot permit monitoring the weight of each load. With either approach, aload flag in the memory 24 denotes whether a load is present on theforks 31. Therefore, if the weight sensor signal indicates a load on theforks, the routine advances to step 174 at which the load flag isexamined. If the load flag already has been set, as occurs when a loadwas picked up previously, the routine ends until the lift motor 51 isoperated again.

Alternatively, finding the load flag not set at step 174 denotes that anew load was just picked up. Now the routine branches to step 176 atwhich the load flag is set. Then at step 178, a count of the loadsstored in memory 24 is incremented. Next the weight of the new load isdetermined at step 180 using the signal from the weight sensor 57 andthe resultant value is stored in a load data table maintained in thememory 24. The length that each load is transported by the industrialvehicle 10 also is measured by starting a load timer at step 182, and ameasurement of the travel distance commences by storing the presentodometer value at step 183. Thereafter the load performance routine 170terminates until the lift motor 51 is operated again.

If upon commencing execution of the load performance routine at step172, a load is not found on the forks 31, a branch occurs to step 184where the load flag is examined. If the load flag is set, then a loadwas just removed from the forks. This determination causes step 186 tobe executed which resets the load flag to denote empty forks. Then atstep 188, the load timer is stopped and at step 190 the load transporttime is stored in the memory 24 with the other data for that load. Nextat step 191, the odometer is read and the travel distance and averagespeed for that distance are computed and stored as part of the loaddata, before advancing to 192. Otherwise if at step 184 the load flagwas found to denote empty forks, the load performance routine jumpsdirectly to step 192 without storing any load data. The load data thusincludes a load count, load weights, transport time, travel distance andaverage speed and may include other types of data, such as powerconsumption and idle time, pertaining to operation of the industrialvehicle.

The load data accumulated in this manner are tabulated during apredefined period, such as an hour, a work shift, or a day. The end ofthat predefined period can be determined at step 192 by the vehiclecontroller 12 reading a real time clock, which event causes the controlsystem 20 to wirelessly transmit the load data via the warehousecommunication system 102 to the warehouse computer system 104 at step194. Instead of using a real time clock, the transmission of the loaddata may occur in response to a command received from the warehousecomputer system 104, which sequentially sends such commands to all theindustrial vehicles in the warehouse. After the transmission of the loaddata, the controller's memory 24 is cleared at step 196 for another dataacquisition period.

The central warehouse computer system 104 receives similar load datafrom all the other industrial vehicles 10 within the warehouse 100. Inthe present example, the central warehouse computer system 104 in FIG. 6analyzes load data to determine the performance and efficiency of eachvehicle. The analysis of the performance and efficiency of a vehicle mayemploy benchmark data from the manufacturer and data gathered fromvehicle operation at the warehouse.

Manufacturers of industrial vehicles typically conduct productivitytests that characterize the performance of a particular vehicle model.For example, a standardized test may be defined as a picking up astandard weight load at a specified height, transporting the load over apredefined path of a known distance, depositing the load at a givenheight, and traveling back to the starting point. During this actionsequence, the vehicle operating parameters are sensed and stored. Theaction sequence is repeated several times to measure the number of suchcycles that the vehicle is capable of performing per hour and produceaverage values for the vehicle operating parameters. This providesproductivity benchmark data for that vehicle model.

The operational data from each industrial vehicle in the warehouse iscompared to the productivity benchmark data to determine whether everyvehicle is operating according to the manufacturer's specifications.Each vehicle's operational data also is compared to similar dataproduced by the other warehouse vehicles during the same time period todetect if one or more of them is operating significantly lessefficiently than the others. Significant deviation from the benchmarkdata or the performance of the other vehicles of the same type at thewarehouse indicates either a mechanical problem or an inefficientoperator. Such deviations are reported to supervisory personnel at thewarehouse to assist them in executing their duty to supervise operatorsand otherwise manage warehouse operations.

Recently gathered operational data also is compared to similar datagathered over past work periods at the warehouse from the sameindustrial vehicle and other vehicles of the same type or model.Significant changes in the current data from that gathered in the pastalso are reported to warehouse supervisory personnel.

The data can also be utilized to determine the amount of time betweenloads for each industrial vehicle and thus how much the entire fleet ofindustrial vehicles is being utilized. The total utilization of thefleet of industrial vehicles can be reviewed to determine whetheradditional vehicles should be obtained for use in the warehouse or onthe other hand whether there are too many vehicles and thus the fleetcan be reduced and still provide efficient warehouse operation.

The vehicle data comparison and analysis can occur at the warehousecomputer system 104 in FIG. 6 and be limited to data from the vehiclefleet at that one facility, can occur at the warehouse managementcomputer system 114 and use data from vehicles at a plurality offacilities in the business enterprise, or can occur at the manufacturercomputer 112 utilizing data from many companies that use that brand ofvehicles. For the latter two processes, the data from several facilitiesare sent to the warehouse management computer system 114 or themanufacturer computer 112 via the Internet 108 or another communicationlink. Thus the operating data from one vehicle can be compared tolocally or globally gathered data.

Another function performed using data that is gathered by the controlsystem 20 prevents use of an unauthorized vehicle in a restricted area.As noted above, certain warehouse environments, such as cold storageareas and areas with potentially explosive atmospheres, require specialindustrial vehicles that are designed to operate in those environments.For example, Type EE industrial vehicles are designed for use in areaswhere flammable materials are stored and a potential explosion or firehazard exists if those materials should leak. Type EE vehicles conformto the spark proof characteristics defined in Underwriters LaboratoriesStandard UL 583. Further, many models of industrial vehicles cannot worksatisfactorily in cold environments which adversely affect the batterypower and hydraulic systems. As a consequence, special models ofindustrial vehicles are designed for use in cold storage areas. Manywarehouses may have both special areas, such as for cold storage or forflammable material storage, as well as other areas for general purposestorage. Operators are trained that only the specially designed vehiclesshould be operated within such special areas.

To reinforce this training, one of the functions that can be implementedby the present industrial vehicle control system 20 is to automaticallydetect when an unauthorized vehicle is approaching a restricted area andprovide a notification to the operator. Thereafter, if the notificationis not heeded and the vehicle enters the restricted area, its operationis disabled. With reference to FIG. 2, this is accomplished by thevehicle controller 12 periodically monitoring its location as indicatedby the GPS receiver 68. That GPS receiver 68 is a conventional devicewhich utilizes the global positioning system comprising a constellationof earth orbiting satellites that continuously transmit signalscontaining the time in which the message was sent and ephemeris dataregarding the precise orbit of the satellite. The GPS receiver 68onboard the industrial vehicle 10 uses the signals from three or more ofthose satellites to determine the precise location of the vehicle.Typically, the GPS receiver determines the longitude and latitude of theindustrial vehicle.

Alternatively, the location of the industrial vehicle 10 can bedetermined from communication with three separate wireless access points106. Each wireless access point 106 is assigned a unique address that isincluded, along with the time of day, in every wireless message sent toan industrial vehicle 10. Each industrial vehicle 10 has an internalclock and is able to tell the time of day that each message in received.From the transmitted time and the received time, the propagation time ofthe message from the wireless access point 106 to the vehicle can becalculated. By receiving messages from at least three wireless accesspoints 106, and by knowing the fixed location in the warehouse of eachof those access points and the respective message propagation times, thevehicle location can be determined using triangulation.

Periodically, such as every few seconds in response to a timedinterrupt, the vehicle controller 12 commences executing a locationcontrol routine 140 depicted by the flowchart in FIG. 10. That routinecommences at step 142 at which the vehicle controller reads the vehiclelocation from the GPS receiver 68. Then at step 144, the vehicle'slocation is compared to a database of alert zones, or areas, definedwithin the warehouse for the associated class of industrial vehicles.

With additional reference to FIG. 11, the exemplary warehouse 100 has aroom 160 in which flammable materials 162 are stored and which room mayhave an explosive environment if those materials should spill or leakfrom their containers. As a consequence, only industrial vehicles 10that are rated for use in such explosive environments are permittedwithin room 160, which is considered to be a restricted area within thewarehouse. In addition, an alert zone 165, having a boundary 166 denotedby a dashed line, is defined within the unrestricted area of thewarehouse 100 in front of the door 164 into the restricted area of room160. For example, this alert zone 165 is defined by an alert location163 in the doorway into the restricted area of room 160, and by adistance D extending around that alert location, thereby specifying asemicircular boundary 166 of the alert zone. Although the definition ofa semicircular or circular alert zone is relatively easy to implement asonly two data items are required (the alert location and the distancetherefrom), other boundary shapes for the alert zone can be implemented.The specification of the alert zone 165 for a particular industrialvehicle 10 is contained in a database of all such areas of thewarehouse, which database is stored in the memory 24 onboard thatvehicle. A similar database defining the restricted areas, such as room160, for the particular vehicle also is provided within it onboardmemory 24.

Thus at step 144, the vehicle controller 12 compares the locationinformation from the GPS receiver 68 to the alert zones specified in itsdatabase. When the location of the industrial vehicle 10 is less thandistance D from the location of the alert location 163, a determinationis made at step 146 that the vehicle is within the alert zone. If so,the program execution branches to step 148 at which a notification isissued to the vehicle operator. For example, the notification isproduced by an annunciator, such as the vehicle's display 55 or theaudible alarm 70 (see FIG. 2). If at step 146, however, a determinationis made that the industrial vehicle 10 is not within one of the definedalert zones, the process branches to step 150 at which any previousalert is deactivated.

Regardless of whether step 148 or 150 is executed, thereafter theprogram advances to step 152 where the present vehicle location iscompared to the database within the vehicle controller memory 24indicating the restricted areas. Then at step 154, a determination ismade whether the industrial vehicle 10 has entered a restricted area.Presumably, the operator will have heeded the alert and not entered therestricted area, in which case, the program execution ends. If contraryto his or her training, the operator failed to heed the alert andcontinued to drive the industrial vehicle 10 into the restricted area,room 160, that event causes the location control routine 140 to branchto step 156. At this time, the vehicle controller 12 disables furtheroperation of industrial vehicle 10. In other words, the vehiclecontroller deactivates the lift motor 51, the traction motor 43, and thesteer motor 47. Other functions of the vehicle also are disabled.Instead of entirely disabling operation, the vehicle controller 12 couldseverely limit the operation, such as by limiting the speed of travel toan extremely slow maximum level or disabling only some functions. Thenat step 158, the vehicle controller 12 transmits a message through thecommunication port 69 and the wireless communication device 71 to thewarehouse communication system 102 to notify the warehouse computersystem 104 that the industrial vehicle has been disabled. In thisdisabled condition, the vehicle cannot be operated until an authorizedperson enters a password into the user input device 67 and re-enablesvehicle operation. Therefore, the message sent to the warehouse computersystem 104 informs supervisory personnel that the industrial vehicle 10has been disabled and gives the location of that vehicle.

In the above implementation, the databases of the alert zones andrestricted areas are stored in the memory 24 onboard each industrialvehicle 10 which enables the location control routine 140 to be executedon each vehicle's controller 12. Alternatively, the databases andlocation control routine 140 can be stored in the warehouse computersystem 104. For each alert zone or a restricted area the databaseindicate the particular vehicles that are allowed to operate therein.Now, each time a vehicle controller 12 reads a location from theassociated GPS receiver 68, that location along with the vehicle'sunique identifier are transmitted wirelessly via the communicationsystem 102 to the warehouse computer system 104. That computer system104 then determines, in a manner similar to that described above,whether the vehicle is within either an alert zone or a restricted areain which that vehicle should not operate. If that is true, a message issent back to the particular industrial vehicle 10 commanding eitherissuance of an operator alert or disabling the vehicle operation, as isappropriate.

The vehicle control system 20 also enables the vehicle to be used in anenergy conserving or “green” manner. Electrical utility companies haverate programs in which the monetary amount charged for electricalconsumption varies at different times of the day. Use of electricityduring peak hours, often the daylight hours, under these rate programstypically costs more than use at off-peak hours, which typically occurduring the night. When the charge of the vehicle's battery 37 diminishesand needs to be recharged, the battery is removed from the vehicle andplaced into a charging station. A battery, that was charged previously,is then inserted into the vehicle for continuing use, while the depletedbattery is being recharged. Therefore, it is desirable to performbattery charging at off peak periods when the electrical utility ratesare the lowest available. Thus it is desirable to operate the industrialvehicle in a manner which will conserve the electrical power duringtimes at which battery replacement requires use of another battery thatwas charged during peak rate periods of the day. In other words, it isdesirable to operate the industrial vehicle in a manner so that thebattery life is prolonged until a time period when a replacement batterythat has been charged during lower electrical rate periods is available.

To accomplish this, the vehicle controller 12 controls operation of thetraction motor 43 so as to limit the maximum speed at which the vehiclecan travel and its rate of acceleration, thereby using battery powermost efficiently. In addition, the lift motor 51 that drives the pumpcan be operated in a similar energy conserving manner. As a consequence,even though the vehicle operator may manipulate the control actuators 41in a manner that normally would produce rapid acceleration or a highvehicle travel speed, the vehicle controller 12 restricts thatacceleration rate and the speed during periods in which the battery 37,if depleted, would have to be replaced by a battery that was chargedduring peak electrical rate periods. On the other hand, during off peakelectrical use periods, such as at night, the limits on the vehicle'sspeed and acceleration are removed so that the vehicle is able tooperate at the maximum speed and rate of acceleration possible.

To implement this energy conservation, the vehicle controller 12 haseither a time of day clock or receives the time of day from thewarehouse computer system 104 via the communication system 102. When itis desired to activate the traction motor 43, the vehicle controllerqueries a table of time periods of limited use that is stored in memory24. If the current time of day is within one of those periods, thevehicle controller 12 limits the commands sent to the traction motorcontrol 27 to regulate the vehicle acceleration and speed for energyconservation.

Another function of the onboard vehicle control system 20 facilitatesthe maintenance, repair and servicing of the industrial vehicle 10. Asnoted previously, a particular industrial vehicle may have any ofnumerous optional features incorporated by the manufacturer based on theorder from a purchaser. When a service technician goes to the warehouseto perform maintenance or repairs on a particular industrial vehicle,that technician needs to know the “as built” configuration of thatvehicle in order to know the proper maintenance procedures to performand how to diagnose the source of a particular problem. Heretofore the“as built” information was not readily available to the servicetechnician on the job site, unless that information was obtained fromthe manufacturer before being the technician was dispatched to thewarehouse. In addition, the technician's service van previously had tocarry an extensive library of manuals for all the different models ofindustrial vehicles that could possibly be serviced by the technician,as well as manuals for all the available optional features.

To facilitate such maintenance and repair work, service informationregarding each specific industrial vehicle 10 is stored within thememory 24 of its vehicle controller 12 in FIG. 2. Service informationincludes trouble shooting manuals, repair manuals, parts manuals,operating manuals, service bulletins, bills of materials, “as built”information related to the particular vehicle, and other informationrelated to maintaining, repairing and servicing the vehicle. Thisinformation can be initially stored by the manufacturer as part of themanufacturing process. Thereafter, as service bulletins are issued,parts numbers change, and other data becomes available, the manufacturercan transfer that data from its computer 112 in FIG. 6 through theInternet 108 to the warehouse 100 where a related vehicle is being used.Upon receipt, the warehouse computer system 104 relays that newinformation via the local area network 105 and the wireless accesspoints 106 to the specific industrial vehicles 10 to which theinformation pertains. In addition, each time that a particularindustrial vehicle 10 is serviced, a service log within its memory 24 isupdated to include references to that servicing so that the log containsan entire service record.

Upon beginning work on a particular industrial vehicle 10, a technicianplugs a laptop computer into the service port 72 of the control systemshown in FIG. 2. In addition or as an alternative to the service port 72for a hardwired connection, a wireless interface, such as one using theBluetooth or WiFi communication protocol, can be provided to communicatebetween the industrial vehicle and the laptop computer. This enables thetechnician to read conventional fault codes generated by the vehiclecontroller 12 which indicate particular problems that the vehicleencountered, as is conventional practice. The technician then can selectone of the fault codes which causes the laptop computer to send a querymessage to the vehicle controller 12 seeking more information related tothe fault code. The vehicle controller responds by accessing the libraryof manuals and service bulletins to obtain information relating to theprocedures to diagnose the cause of the fault code. Thus the vehiclecontroller 12 automatically accesses the proper materials in its libraryto aid the technician in servicing the industrial vehicle. Furthermore,once the problem has been diagnosed, the vehicle controller 12 alsoautomatically accesses the respective portions of the service manualsdescribing the procedure for rectifying the problem and how to replacecomponents.

In addition, the laptop computer connected via the service port 72 canaccess the “as built” information for the particular vehicle beingserviced which greatly aids the technician understanding of the deviceson the vehicle and their operation. Once the correct service proceduresare identified in the manuals, the vehicle controller 12 also producesan indication of the parts that are required to effect the repairincluding their part numbers. Alternatively, the user input device 67 ofthe vehicle can be employed to access this information which then ispresented to the technician via the onboard display 55. By storing suchinformation in the vehicle's memory 24, the service technician is notrequired to gather detailed information about the specific vehicle to beserviced nor does the service van have to carry a complete library forservicing all the different vehicle models and configurations that arepossible.

The foregoing description was primarily directed to a certainembodiments of the industrial vehicle. Although some attention was givento various alternatives, it is anticipated that one skilled in the artwill likely realize additional alternatives that are now apparent fromthe disclosure of these embodiments. Accordingly, the scope of thecoverage should be determined from the following claims and not limitedby the above disclosure.

1. A method for controlling an industrial vehicle that carries aplurality of loads on which indicators have been placed, said methodcomprising: electronically reading a given indicator on a load beingcarried by the industrial vehicle to obtain a load identifier; employingthe load identifier to obtain data from a database wherein that dataindicates whether the load being carried requires delicate handling; andin response to data obtained from a database, restricting operation ofthe industrial vehicle to provide delicate handling of the load.
 2. Themethod as recited in claim 1 wherein when the given indicator designatesthat the load being carried requires delicate handling, the operation ofthe industrial vehicle is held to a slower speed than when the givenindicator does not designate that the load being carried requiresdelicate handling.
 3. The method as recited in claim 1 whereinelectronically reading an indicator on a load comprises operating a loadsensor selected from the group consisting of a radio frequencyidentification tag reader, a bar code reader, and a device that utilizesa communication protocol defined by IEEE standard 1902.1.
 4. The methodas recited in claim 1 wherein each indicator uniquely identifies one ofthe plurality of loads.
 5. The method as recited in claim 1 wherein theindicators designate whether each of the plurality of loads requiresdelicate handling.
 6. The method as recited in claim 1 whereinrestricting operation comprises limiting a travel speed of theindustrial vehicle to less than a predefined level.
 7. The method asrecited in claim 1 wherein restricting operation comprises limiting arate of travel acceleration of the industrial vehicle to less than apredefined level.
 8. The method as recited in claim 1 whereinrestricting operation comprises limiting a speed at which the load beingcarried is raised and lowered to less than a predefined level.
 9. Themethod as recited in claim 1 further comprising electrically detectingwhen the given load no longer is being carried by the industrialvehicle; and terminating the restricting operation of the industrialvehicle.
 10. The method as recited in claim 9 wherein detecting when thegiven load no longer is being carried by the industrial vehiclecomprises sensing a force applied to a component of the industrialvehicle.
 11. The method as recited in claim 1 wherein electronicallyreading the given indicator is performed in response to sensing a forceapplied to a component of the industrial vehicle.
 12. The method asrecited in claim 1 wherein electronically reading the given indicator isperformed in response to a command to move a component of the industrialvehicle.
 13. The method as recited in claim 1 further comprisingcreating a computer implemented database that identifies indicatorswhich are associated with loads that are fragile; and whereindetermining whether the load being carried requires delicate handlingcomprises querying the database and producing an indication whether theload being carried is fragile.
 14. The method as recited in claim 13wherein the database is contained in a computer that is located remotelyfrom the industrial vehicle; and further comprising producinginformation in response to electronically reading the given indicator,transmitting the information via a wireless communication link to thecomputer, using the information to query the database, and transmittingthe indication from the computer to the industrial vehicle via thewireless communication link.
 15. The method as recited in claim 1wherein the indicators are either radio frequency identification tags orbar codes.
 16. A method for controlling an industrial vehicle thatcarries a plurality of loads on which indicators have been placed, saidmethod comprising: receiving a command to move a component of theindustrial vehicle. in response to receiving the command, electronicallyreading a given indicator on a load being carried by the industrialvehicle to obtain a load identifier; employing the load identifier todetermine whether the load being carried requires delicate handling, inwhich situation a delicate load indication is produced; and in responseto the delicate load indication, restricting operation of the industrialvehicle to provide delicate handling of the load.
 17. The method asrecited in claim 16 wherein restricting operation of the industrialvehicle comprises operating the vehicle a slower speed than when thegiven indicator does not designate that the load being carried requiresdelicate handling.
 18. The method as recited in claim 16 whereinrestricting operation of the industrial vehicle comprises limiting atravel speed of the industrial vehicle to less than a predefined level.19. The method as recited in claim 16 wherein restricting operation ofthe industrial vehicle comprises limiting a rate of travel accelerationof the industrial vehicle to less than a predefined level.
 20. Themethod as recited in claim 16 wherein restricting operation of theindustrial vehicle comprises limiting a speed at which the load beingcarried is raised and lowered to less than a predefined level.
 21. Themethod as recited in claim 16 wherein each indicator uniquely identifiesone of the plurality of loads.
 22. The method as recited in claim 16wherein the indicators designate whether each of the plurality of loadsrequires delicate handling.
 23. The method as recited in claim 22further comprising creating a computer implemented database thatidentifies indicators which are associated with loads that are fragile;and wherein the delicate load indication is produced in response toquerying the database with the given indicator read from a load.
 24. Themethod as recited in claim 23 wherein the database is contained in acomputer that is located remotely from the industrial vehicle; andfurther comprising producing information in response to electronicallyreading the given indicator, transmitting the information via a wirelesscommunication link to the computer, using the information to query thedatabase, and transmitting the indication from the computer to theindustrial vehicle via the wireless communication link.
 25. The methodas recited in claim 16 further comprising electrically detecting whenthe given load no longer is being carried by the industrial vehicle; andterminating the restricting operation of the industrial vehicle.
 26. Themethod as recited in claim 25 wherein detecting when the given load nolonger is being carried by the industrial vehicle comprises sensing aforce applied to a component of the industrial vehicle.